Pilot burner-thermoelectric generator assembly



Feb. 26, 1957 5, 1L5 I 2,783,290-

PILOT BURNER-THERMOELECTRIC GENERATOR ASSEMBLY Filed April 5, 1954 IN V EN TOR.

Stephen L. Kile BY United States PILOT BURNER-THERMOELECTRIC GENERATOR ASSEMBLY Stephen L. Kile, Whitefish Bay, Wis., assignor to Milwaukee Gas Specialty Company, Milwaukee, Wis., a corporation of Wisconsin Application April 5, 1954, Serial No. 420,782 18 Claims. (Cl. 136-4) This invention relates to improvements in fuel burners and more particularly to pilot burner-thermoelectric generator assemblies.

Improvements in gaseous fuel burning appliances, for example kitchen ranges, include the use of a constantly burning pilot burner which is mounted in coacting relationship with one or more main burners, for example an oven burner. Low consumption is desirable in constantly burning pilot burners, not only from the standpoint of fuel economy, but also in order to prevent the generation of unwanted qantities of heat. It is desirable, however, that the pilot burner generate suflicient heat for the energization of a thermoelectric generator, for example a thermocouple for powering a control circuit. In addition to low fuel consumption, it is important that the afore mentioned burner have good flame quality, i. e. a blue flame as distinguished from a yellow, or poor quality flame, and also that said burner have good flame stability. Without good stability characteristics the burner flame cannot Withstand concussions or air currents caused, for example, by opening or closing the door of an oven in which said burner is mounted.

With the above in mind, it is a general object of the present invention to provide an improved low consumption fuel burner assembly having improved flame quality and flame stability characteristics, said burner being. of the non-aerated type, i. e., one in which no primary air is mixed with the fuel before said fuel is emitted from the burner.

Another object of the invention is to provide an improved pilot burner-thermoelectric generator assembly having the aforementioned improved flame characteristics and including a thermoelectric generator which can be readily removed from said assembly. r

Another object of the invention is to provide an im-' proved assembly of the character described having an elongated flame port of reduced width alfording a substantially increased area immediately adjacent said port for the intermixture of the fuel emitted from said port with the ambient air.

Another object of the invention is to provide an improved burner of the aforementioned character in which fluctuations in fuel pressure have no substantial adverse effect on the supply of air to the flame and the disposal of the products of combustion therefrom, and hence a clean flame is maintained by said burner regardless of pressure fluctuations.

More specifically, it is an object of the invention to provide a burner having a downwardly opening flame port disposed on the underside of a surface to be heated,

for example the surface of a horizontally disposed thermoelectric generator, wherefore the hot products of combustion rise by convection and allow free and continuous access of fresh air to the flame from below, the rising products of combustion having no substantial deleterious effect on the mixture of the air with the fuel, regardless of fuel pressure fluctuations.

Another specific object of the invention is to provide an r 2,783,290 Ice Patented Feb. 26, 1957 improved assembly of the character described wherein the flame port lies in a substantially vertical U-shaped plane underneath the thermoelectric generator and adjacent the hot junction of the latter, the fuel being emitted from said flame port in substantially horizontal directions inwardly of the plane of said flame port, the conformation of said flame port and its disposition providing substantial protection for the flame base, anchoring the latter to the flame port and affording resistance to the effects of concussion, drafts and the like, for example, those commonly encountered in range ovens.

Another object of the invention is to provide an improved burner assembly of the character described wherein the U-shaped flame port may be spaced from the hot junction of the thermoelectric generator and disposed with respect thereto so that an uncompensated unidirectional component of the fuel velocity directs fuel flow toward, and hence disposes the flame in contact with, said hot junction.

Further objects and advantages of the invention will become apparent as the description proceeds, reference being had to the accompanying drawing illustrating one complete embodiment of the invention, and wherein like characters of reference indicate the same parts in all of the views:

Figure 1 is a fragmentary side elevational view of a pilot burner-thermoelectric generator assembly constructed in accordance with the invention and mounted in coacting relationship with a main burner, parts of the latter being broken away and shown in section;

Figure 2 is a bottom view of the pilot burner-thermoelectric generator assembly shown in Figure 1;

Figure 3 is an enlarged longitudinal sectional view taken along the line 3--3 of Figure 1;

Figure 4 is an enlarged fragmentary perspective view taken along the line 4-4-of Figure 1; and

Figure 5 is an enlarged end elevational view of the pilot burner-thermoelectric generator assembly as viewed from the right in Figure 1.

Referring to Figure 1 of the drawing, the numeral 10 indicates a pilot burner-thermoelectric generator assembly constructed in accordance with the invention and mounted in a coacting relationship with a main burner 11, for example a range oven burner having downwardly and outwardly directed'flame ports 12. The assembly 10 may be fixed to a bracket 13, as by bolt 14 and nut 15, said bracket, in turn, being suitably fixed to a wall 16 of the compartment in which the main burner 11 is mounted.

The pilot burner-thermoelectric generator assembly 10 comprises a body 17 formed with a cross bore 18 for receiving the attaching bolt 14, said body also being formed with an internally threaded bore 19 for the reception of a spud fitting 20, the latter having a restricted orifice 21. The spud 20 may be supplied with fuel through a pipe 42 having a connector nut 43 threaded into said spud as shown. The body 17 also has a second bore 22 provided with a portion of reduced diameter 23, and having counterbores 24 and 25 at its opposite ends.

An' angular passage 29 alfords communication between the bores 19 and 22, said passage opening into the conical' inner end wall 51 of the bore 19 at a point offset laterally from the apex thereof. The passage 29 opens into the bore 22 adjacent the portion 23 thereof as shown.

A cylindrical tube 26 is suitably coaxially fixed, as by welding, within the counterbore 25 and has an inner diameter substantially equal to the bore portion 23 as shown. The tube 26 is provided with an end wall 27 having a central bore 28.

The assembly 10 includes a thermoelectric generator 30 removably positioned within the body 17 and tube 26 as shown. The. generator 30 includes a cylindrical tubular outer thermocouple element 31 and a coaxial inner thermocouple element 38, said thermocouple element being suitably joined at one end to provide a hot junction 32. The generator 39 may be provided with a coaxial type lead having an outer tubular conductor 33 and an insulated inner conductor 34. The outer lead conductor 33 is connected to the outer thermocouple element 31 through a connecting sleeve 35 having an annular shoulder 36 and forming a cold junction with the thermocouple element 31 at 37. The inner lead conductor 34 is connected to the inner thermocouple element 38 within the sleeve 35 to provide a second cold junction 39.

The generator 39 is fixed in operative position within the body 17 and tube 26 by means of a connector nut 40 threaded into the counterbore 24 and engaging the annular shoulder 36 to clamp the latter between said nut and an annular shoulder 41 providedby said counterbore. The outer thermocouple element 31 is preferably cylindrical in shape and has a snug fit within the bore 28 of the end Wall 27. As shown, the hot junction 32 projects a short distance beyond the end wall 27. The inner surface of the tube 26 is spaced from the outer surface of the thermocouple element 31 to provide an annular fuel passage therebetween. In effect, the tube 26 forms a jacket in which the thermocouple element 31 is enclosed.

The assembly 16. has a novel flame port structure provided by an elongated axially extending slot 44 in the side wall of the tube 26, extending inwardly from the outer end of said tube directly below the thermocouple element 31. As shown most clearly in Figure 4, the slot 44 has generally parallel side edges 46 and 47 extending in generally vertical planes, said side edges being cnnected by an arcuate end edge 48 providing said slot with a margin of U-shaped conformation. The end wall 27 is cut away between the side edges 46 and 47 of the slot 44, as at 45. The tube 26 and its slot 44 form, with the cylindrical wall of the outer thermocouple element 31, an elongated generally U-shaped flame port 50 having a length substantially coextensive with the margin of the slot 44, and having a width substantially coextensive with the spacing between the inner surface of the tube 26 and the thermocouple element 31 at the margin of said slot. The flame port 50 lies in a U-shaped substantially vertical plane and is bounded by the margin of the slot 44 at the inner surface of the tube 26 and the dot and dash line 49 shown in Figure 4, the latter indicating the intersection of the aforementioned U-shape-d vertical plane with the surface of the thermocouple element 31.

From the above, it is apparent that opposite portions of the U-shaped flame port 50 lie in substantially parallel vertical planes, said flame port having substantial length and relatively narrow width. It is also apparent that the width of the slot 44 is substantially greater than the radial spacing between the tube 26 and the thermocouple element 31, i. e., the width of the flame port.

Illustrative of the dimensional relationships existing between the various parts of a pilot burner-thermoelectric generator assembly constructed in accordance with the invention, one form thereof utilizes a thermocouple wherein the diameter of the cylindrical thermocouple member 31 is .187 inch, and said couple projects .125 inch beyond the end wall 27. In the aforedescribed assembly, the width of the slot 44 indicated by thedimension B in Figure 4, is .145 inch, and the length of said slot, indicated by the dimension C in Figure 4, is .192 inch. Therefore, in the instant assembly the length of the margin of slot 44 is .472 inch. The radial spacing between the tube 26 and the element 31, indicated by the dimension A in Figure 4, and constituting the width of the flame port 50, is .018 inch. The length of the flame port 50 is .382 inch, thus providing a flame port area of .00687 square inch. The spud in the instant assembly has an orifice diameter of .008 inch providing an orifice area of .00005 square inch. With'these relationships,

the flame port area is approximately 137 times that of the orifice 21.

The aforementioned dimensions are merely illustrative of the relationships which produce the improved flame characteristics, and it is obvious that the invention should not be limited to the precise dimensions set forth.

In the operation of the improved pilot burner thermoelectric generator assembly 10, fuel under pressure flows from the orifice 21, through the bores 19 and 29 and into the annular fuel passage within the tube 26, through which it flows toward the flame port 50. By virtue of the fact that the cross-sectional area of the fuel passages through which the fuel flows from the orifice to the flame port is substantially greater than that of said orifice, the velocity of the fuel at the flame port is very low.

Since during normal operation of the assembly 10, the annular fuel passage within the tube 26 is filled with fuel, said fuel flows from the flame port 50 throughout the length of said port. As indicated by the broken arrows in Figure 4, the fuel flows in a generally horizontal plane inwardly with respect to the margins of the slot 44. If desired, the underside of the thermocouple element 31 may be flattened within the margins of the slot 44 to provide a flat horizontal surface along which the opposing fuel streams can travel in coplanar relationship;

Because of the elongated nature and limited width of the flame port 50, the fuel issues from said port in a sheet-like stream. This provides a substantially increased flame base length and thereby affords substantially improved contact of the issuing fuel with the ambient air in the immediate vicinity of the flame port. As a result, a relatively large, blue, ball-shaped flame is produced, said flame wiping the undersurface of the generator wall 31. The flame produced is clean, i. e. free from yellow tipping, and is highly resistant to drafts and concussions, for example those ordinarily created in a range oven as a result of opening and closing the oven door. The flame produced provides ample heat for proper operation of the generator 30.

The part of the fuel stream issuing from the port 50 adjacent the edge portion 46 of the slot 44, and the part of the fuel stream of equal size issuing from said port adjacent the opposite edge portion 47 of said slot are directed generally horizontally toward each other so that said stream portions meet and are mutually deflected downwardly. This opposition of said fuel stream portions prevents the velocity of either of said stream portions from shifting the mass of burning fuel transversely in the direction of which eitherstream portion is emitted from the flame port. This keeps the flame centered below the generator 30.

As distinguished from the mutual velocity compensation afforded by opposition of the aforementioned opposing fuel stream portions, the portions of the fuel stream emitted from the flame port adjacent the end portion 48 of the slot 44 are not directly opposed by any other fuel stream portions. This afifords an uncon pensated unidirectional component of the fuel stream velocity which is directed longitudinally of the slot 44 and axially outwardly along the undersurface of the generator wall 32 toward the hot junction 32. This fuel velocity component is effective to move the mass of burning gas axially outwardly, so that a portion of the flame extends axially beyond the slot 44 and into coacting rela tion with the hot junction 32 as shown in Figure l.

The portion of the fuel stream having the aforementioned uncompensated unidirectional velocity components, while being effective to position a portion of the flame beyond end of the slot 44 is nevertheless substantially smaller in volume than the remaining portion of the fuel stream comprising the opposed transversely directed fuel stream portions. Because of the relatively small magnitude of the aforementioned uncompensated velocity component, the flame is never caused to extend substantially beyond 1 hot junction 32 during normal fluctuations in fuel line pressure. As a result, the output of the generator 36 remains uniform, even though the line fuel pressure may fluctuate.

The magnitude and the flame shifting effect of the fuel stream portion having the uncompensated axial velocity component are dependent upon the dimensions of the slot 44, and said dimensions may vary within the concept of the invention. If, for example, the slot dimension C is increased or the dimension B decreased, the ratio of eifluxing fuel having an uncompensated axial velocity component to the total fuel effluxed is decreased, whereas a decrease in the dimension'C or an increase in the dimension B increases the ratio of the eflluxing fuel having said velocity component. The dimensions ,setforth hereinbefore are illustrative of the size slot 44 and the relation of slot width to length which produces, in the illustrated structure, efilux from the flame port of sufficient fuel having an uncompensated axial component to position the flame so that a portion thereof is disposed axially outwardly of the slot 44 for proper coaction with the hot junction 32 located well beyond the wall 27 as shown. In the illustrated structure approximately one-third of the fuel efliuxing from the burner port has an uncompensated axially outwardly directed velocity component.

The structure of the improved burner-thermoelectric generator assembly, by compensating or neutralizing the velocity of a major portion of the fuel stream issuing from the flame port, and by utilizing the uncompensated axial velocity component of the remaining portion of said fuel stream to shift the flame axially outwardly in the manner described, provides a lazy, ball-shaped, blue flame for efliciently heating the generator hot junction, even though said hot junction is spaced horizontally from the flame port.

The burner port construction and the disposition of said port on the, underside of the generator provides efficient removal of the hot products of combustion from the flame and affords continuously free access of the ambient air to the flame. The hot products of combustion rise by convection, and the fresh ambient air contacts the flame from below, permitting said air to diffuse freely into the emitted gases. without interference from products of combustion. It is such interference that ordinarily causes yellow tipping in conventional burners.

. Because of this novel operation, the improved burner is not susceptible of yellow-tipping even though the line fuel pressure may increase to substantially above normal.

- The location of said port radially inwardly'of the margin of the slot 44 provides protection for the flame base against drafts or air currents flowing transversely across the slot 44. The flame base is thereby effectively anchored to the flame port, since ordinarily, drafts cannot ventilate the base of the flame to extinguish the latter. Ventilation of outer parts of the flame, of course, have no deleterious effect on said flame.

The improved assembly permits the use therein of a thermocouple 30 of standard construction. The thermocouple 39 can be quickly and easily removed from the assembly by loosening the nut 40 and pulling the thermocouple out through the counterbore 34. Similarly, the spud 20 can be unscrewed from the body 17 after loosening the nut 23 and detaching thesupply line 32.

While the improved pilot burner-thermoelectric genera tor assembly illustrated in the drawing is mounted horizontally, experience has shown that assemblies of this type work satisfactorily with the hot junction end thereof canted upwardly as much as 60 from the horizontal, i. e. 30 from the vertical.

The specific illustrations and corresponding description are used for the purposes of disclosure only and are not intended to impose unnecessary limitations on the claims, or to confine the patented invention to a particular use. Various changes and modifications may be made without departing from the spirit of the invention, and all of such changes are contemplated as may come within" the scope of the'claims.

What is claimed as the invention is:

1. A pilot burner-thermoelectric generator assembly, comprising a horizontally disposed thermoelectric generator having a side wall and having a hot junction at one end, a jacket on said generator forming therewith a fuel passage, said jacket having a wall portion spaced below said generator side wall adjacent said hot junction, said jacket wall portion being formed with a bottom opening to provide a flame port, and means for causing fuel flow within said jacket and out of said bottom flame port, whereby ignition of said fuel provides a ball-shaped flame for heating said hot junction.

2. A pilot burner-thermoelectric generator assembly, comprising, a horizontally disposed thermoelectric generator having a sidewall and having a hot junction at.

one end, a jacket on said generator forming therewith a fuel passage, means for causing fuel flow through said fuel passage, said jacket terminating short of said hot junction and having a wall portion spaced below said generator side wall adjacent said hot junction said jacket wall portion being formed with a bottom opening, said opening having a width substantially greater than the spacing between said wall portion and generator side wall, and providing with said generator side wall an elongated flame port having a length substantially coextensive with the length of said opening margin and a width substantially coextensive with the spacing between said wall portion and generator side wall at said opening margin, said flame port providing for emission of fuel therefrom along said generator side wall and inwardly from said opening margin.

3. A pilot burner-thermoelectric generator assembly, comprising, a horizontally disposed thermoelectric generator having a side wall and having a hot junction at one end, a jacket on said generator forming therewith a fuel passage, means for causing fuel flow through said fuel passage, said jacket terminating short of said hot junction and having a bottom wall portion spaced below said generator side wall and an end Wall adjacent said hot junction, said bottom wall portion being formed with an opening adjacent said end wall, and said end wall being cut away at said opening, said bottom opening having a width substantially greater than the spacing between said bottom wall portion and said generator side wall and providing with said generator side wall an elongated flame port having a length substantially coextensive with the length of said opening margin and a width substantially coextensive with the spacing between said bottom wall portion and said generator side wall at said opening margin, said flame port providing for emission of fuel therefrom along said generator side wall and inwardly from said opening margin, whereby ignition of fuel at said flame port produces a clean, stable, ball-shaped flame lying under and wiping the underside of said generator adjacent said hot junction.

4, A pilot burner-thermoelectric generator assembly, comprising, a horizontally disposed thermoelectric gener ator having a hot junction at one end, a horizontally disposed jacket within which said generator is removably enclosed and forming therewith an annular fuel supply passage, means for causing fuel flow through said fuel passage, said jacket having an end wall through which the hot junction end of said generator projects, said jacket also having a side wall portion spaced below said generator and formed with a downwardly facing opening adjacent said end wall, said opening having a width substantially greater than the spacing between said jacket and generator and providing with said generator an elongated flame port having a length substantially coextensive with the length of said opening margin and a width substantially coextensive with the spacing between said jacket and generator at said opening margin, whereby ignition of 7 fuel at said flame port produces a clean, stable, ballshaped flame lying under and wiping the underside of said generator adjacent said hot junction.

5. A pilot burner-thermoelectric generator assembly, comprising, a horizontally disposed thermoelectric generator having a hot junction at one end, a horizontally disposed jacket within which said generator is removably enclosed and forming therewith an annular fuel supply passage, means for causing fuel flow through said fuel passage, said jacket having an end wall through which the hot junction of said generator projects, said jacket also having a side wall portion spaced below said generator and formed with a downwardly facing elongated opening extending longitudinally inwardly from said end wall, said end wall being cut away at said opening, and said opening having a width substantially greater than the spacing between said jacket and generator and providing with said generator an elongated generally U-shaped flame port having a length substantially coextensive with the length of said opening margin and a width substantially coextensive with the spacing between said jacket and generator at said opening margin, whereby ignition of fuel at said flame port produces a clean, stable, ball-shaped flame lying under and wiping the underside of said generator adjacent said hot junction.

6. A pilot burner-thermoelectric generator assembly, comprising, a horizontally disposed thermoelectric generator having a hot junction at one end, a horizontally disposed jacket within which said generator is removably enclosed and forming therewith an annular fuel supply passage, means for causing fuel flow through said fuel passage, said jacket having an end wall through which the hot junction end of said generator projects, said jacket also having a side wall portion spaced below said generator and formed with a downwardly facing elongated opening extending longitudinally inwardly from said end wall and having substantially straight longitudinally extending opposite side edges and an arcuate inner end edge connecting said side edges, said end wall being cut away between the side edges of said opening, and said opening having a width substantially greater than the spacing between said jacket and generator and providing with said generator an elongated U-shaped flame port having a length substantially coextensive with the length of said opening margin and a width substantially coextensive with the spacing between said jacket and generator at said opening margin, whereby ignition of fuel at said flame port produces a clean, stable, ball-shaped flame lying under and wiping the underside of said generator adjacent said hot junction.

7. A pilot burner-thermoelectric generator assembly, comprising, a horizontally disposed generally cylindrical thermoelectric generator having a hot junction at one end, a horizontally disposed tubular cylindrical jacket within which said generator is removably enclosed in coaxial spaced relation and forming therewith an annular fuel supply passage, means for causing fuel flow through said fuel passage, said jacket having a centrally bored end wall through which the hot junction end of said generator snugly projects, said jacket also having a side wall portion spaced below said generator and formed with an elongated, downwardly facing opening extending axially inwardly from said end wall and having substantially straight axially extending opposite side edges and an arcuate inner end edge connecting said side edges, said end wall being cut away between the side edges of said opening, and said opening having a width substantially greater than the spacing between said jacket and generator and providing with said generator an elongated U-shaped flame port having a length substantially coextensive with the length of said opening margin and a width substantially coextensive with the spacing between said jacket and generator at said opening margin, whereby ignition of fuel at said flame port produces a clean, stable, ball- 8 shaped flame lying under and wiping the underside of said generator adjacent said hot junction.

8. A pilot burner-thermoelectric generator assembly, comprising a thermoelectric generator having a downwardly facing surface and a hot junction, and burner port means positioned to supply fuel adjacent the underside of said generator surface at a point spaced from said hot junction, said port means having first portions from which fuel is effluxed in opposing horizontal stream portions to neutralize the effect of the velocity of said stream portions on the relative horizontal position of the flame produced by burning of said eflluxed fuel, said port means also having a second portion from which fuel is effluxed, said latter fuel having an uncompensated velocity component directed at said first mentioned opposing fuel stream portions and toward said hot junction, whereby to offset portions of the eflluxed fuel mass and hence said flame horizontally from said port means toward said hot junction, whereby to position said flame in coacting relation with said hot junction.

9. A pilot burner-thermoelectric generator assembly, comprising a horizontally disposed cylindrical thermoelectric generator having a hot junction at one end, and burner port means positioned to supply fuel adjacent the undersurface of said generator at a point spaced from said hot junction, said port means having first portions from which fuel is etfluxed in opposing transverse horizontal stream portions to neutralize the effect of the velocity of said stream portions on the transverse position of the flame produced by burning of said eflluxed fuel, said port means also having a second portion from which fuel is eflluxed, said latter fuel having an uncompensated velocity component directed axially of said generator at said first mentioned opposing fuel stream portions and toward said hot junction whereby to offset portions of the eflluxed fuel mass and hence said flame axially from said port means toward said hot junction, whereby to position said flame in coacting relation with said hot junction.

10. A pilot burner'thermoelectric generator assembly, comprising a thermoelectric generator having a downwardly facing surface and a hot junction, and burner port eans positioned to supply fuel adjacent the underside of said generator surface at a point spaced from said hot junction, said port means having first portions from which fuel is eflluxed in opposing horizontal stream portions to neutralize the effect of the velocity of said stream portions on the relative horizontal position of the flame produced by burning of said effluxed fuel, said port means also having a second portion from which fuel is effluxed, said latter fuel having an uncompensated velocity component directed at said first mentioned opposing fuel stream portions and toward said hot junction whereby to offset portions of the effluxed fuel mass and hence said flame horizontally from said port means toward said hot junction, whereby to position said flame in coacting relation with said hot junction, the volume of fuel elfiuxed from said second portion of said port means being not greater than the volume of fuel eflluxed from said first portions of said port means.

11'. A pilot burner-thermoelectric generator assembly, comprising a thermoelectric generator having a side wall portion inclined at least 30 from the vertical and having a hot junction, and a jacket for said generator forming therewith a fuel passage, said jacket having a wall portion below said generator side wall portion and adjacent said hot junction, said jacket Wall portion being formed with an opening to provide a flame port, whereby ignition of fuel at said flame port provides a generally ball shaped flame wiping the underside of said generator to heat said hot junction. 7

12. A pilot burner-thermoelectric generator assembly, comprising a thermoelectric generator having a side wall portion inclined at least 30 from the vertical and having a hot junction, and a jacket for said generator forming therewith a fuel passage, said jacket having a wall portion t Q spaced below said generator side wall portion and adjacent said hot junction, said jacket wall portion being formed with an opening having a width substantially greater than the spacing between said jacket wall portion and generator side Wall portion and providing with said generator side wall portion an elongated flame port having a length substantially coextensive with the length of said opening margin and a width substantially coextensive with the spacing between said wall portion and generator side wall portion at said opening margin, said flame port providing for emiss'ion of fuel therefrom along said generator side wall por tion and inwardly from said opening margin.

13. A pilot burner thermoelectric generator assembly, comprising a thermoelectric generator having an operative position inclined at least 30 from the vertical and having a hot junction, and a jacket enclosing said generator and forming therewith an annular fuel passage, said jacket having a wall portion below said generator and formed with an opening adjacent said hot junction to provide a flameport, whereby ignition of fuel at said flame port provides a generally ball shaped flame wiping the underside of said generator to heat said hot junction.

14. A pilot burner-thermoelectric generator assembly, comprising a thermoelectric generator having an operative position inclined at least 30 from the vertical and having a hot junction, and a jacket within which said generator is removably enclosed and forming therewith an annular fuel passage, said jacket having a wall portion spaced below said generator and formed with an opening adjacent said hot junction to provide a flame port, whereby ignition of fuel atsaid flame port provides a generally ball shaped frame wiping the underside of said generator to heat said hot junction.

15. A pilot burner-thermoelectric generator assembly, comprising a thermoelectric generator having a side wall portion inclined at least 30 from the vertical and having a hot junction, and a jacket for said generator forming therewith a fuel passage, said jacket having a side wall portion spaced below said generator side wall portion and having an end wall portion adjacent said hot junction, said jacket side wall portion being formed with a downwardly facing opening adjacent said end wall portion, and said end wall portion being cut away at said opening to provide therewith a flame port, whereby ignition of fuel at said flame port provides a generally ball shaped flame for heating said hot junction.

16. A pilot burner-thermoelectric generator assembly, comprising a thermoelectric generator having a side wall portion inclined at least 30 from the vertical and having a hot junction, and a jacket for said generator forming is therewith a fuel passage, said jacket having a side wall portion spaced below said generator side wall portion and having an end wall portion adjacent said hot junction, said jacket side wall portion being formed with a downwardly facing opening extending longitudinally inwardly from said end wall and having longitudinally extending opposite side edges and an arcuate inner edge connecting said side edges, said end wall being cut away between the side edges of said opening to provide therewith a flame port, whereby ignition of fuel at said port provides a generally ball shaped flame for heating said hot junction.

17. A pilot burner-thermoelectric generator assembly, comprising a thermoelectric generator having a downwardly facing surface inclined at least 30 from the vertical and a hot junction, and burner port means positioned to supply fuel adjacent the underside of said generator surface at a point spaced from said hot junction, said port means'having first portions from which fuel is efliuxed in opposing stream portions to neutralize the effect of the velocity of said stream portions on the relative position of the fiame produced by burning of said effluxed fuel, said port means also having a second portion from which fuel is efltuxed, said latter fuel having an uncompensated velocity component directed at said firstmen-tioned opposing fuel stream portions and toward said hot junction, whereby to offset portions of the efliuxed fuel mass and hence said flame toward said hot junction and into coacting relation therewith.

18. A pilot burner-thermoelectric generator assembly having walls defining a fuel passage, one of said walls being inclined at least 30 from the vertical and formed with a flame port for downwardly directed emission of fuel,

said assembly comprising dissimilar thermoelectric generator elements joined to provide a hot junction adjacent said flame port, at least one of said thermoelectric generator elements forming one of the walls defining said fuel passage, ignition of fuel emitted from said flame port providing a generally ball shaped flame below and in heating proximity to said hot junction.

References Cited in the file of this patent UNITED STATES PATENTS 1,204,278 Keller Nov. 7, 1916 1,552,438 Leach Sept. 8, 1925 2,349,306 Ray May 23, 1944 2,407,517 Ray Sept. 10, 1946 FOREIGN PATENTS 335,865 France Dec. 19, 1903 9,486 Great Britain I an. 7, 1909 

